// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_FORMATS_MP4_AVC_H_
#define MEDIA_FORMATS_MP4_AVC_H_

#include <stddef.h>
#include <stdint.h>

#include <memory>
#include <vector>

#include "media/base/media_export.h"
#include "media/formats/mp4/bitstream_converter.h"

namespace media {

struct SubsampleEntry;

namespace mp4 {

    struct AVCDecoderConfigurationRecord;

    class MEDIA_EXPORT AVC {
    public:
        static bool ConvertFrameToAnnexB(int length_size,
            std::vector<uint8_t>* buffer,
            std::vector<SubsampleEntry>* subsamples);

        // Inserts the SPS & PPS data from |avc_config| into |buffer|.
        // |buffer| is expected to contain AnnexB conformant data.
        // |subsamples| contains the SubsampleEntry info if |buffer| contains
        // encrypted data.
        // Returns true if the param sets were successfully inserted.
        static bool InsertParamSetsAnnexB(
            const AVCDecoderConfigurationRecord& avc_config,
            std::vector<uint8_t>* buffer,
            std::vector<SubsampleEntry>* subsamples);

        static bool ConvertConfigToAnnexB(
            const AVCDecoderConfigurationRecord& avc_config,
            std::vector<uint8_t>* buffer);

        // Verifies that the contents of |buffer| conform to
        // Section 7.4.1.2.3 of ISO/IEC 14496-10.
        // |subsamples| contains the information about what parts of the buffer are
        // encrypted and which parts are clear.
        // Returns true if |buffer| contains conformant Annex B data
        // TODO(acolwell): Remove the std::vector version when we can use,
        // C++11's std::vector<T>::data() method.
        static bool IsValidAnnexB(const std::vector<uint8_t>& buffer,
            const std::vector<SubsampleEntry>& subsamples);
        static bool IsValidAnnexB(const uint8_t* buffer,
            size_t size,
            const std::vector<SubsampleEntry>& subsamples);

        // Given a |buffer| and |subsamples| information and |pts| pointer into the
        // |buffer| finds the index of the subsample |ptr| is pointing into.
        static int FindSubsampleIndex(const std::vector<uint8_t>& buffer,
            const std::vector<SubsampleEntry>* subsamples,
            const uint8_t* ptr);
    };

    // AVCBitstreamConverter converts AVC/H.264 bitstream from MP4 container format
    // with embedded NALU lengths into AnnexB bitstream format (described in ISO/IEC
    // 14496-10) with 4-byte start codes. It also knows how to handle CENC-encrypted
    // streams and adjusts subsample data for those streams while converting.
    class AVCBitstreamConverter : public BitstreamConverter {
    public:
        explicit AVCBitstreamConverter(
            std::unique_ptr<AVCDecoderConfigurationRecord> avc_config);

        // BitstreamConverter interface
        bool ConvertFrame(std::vector<uint8_t>* frame_buf,
            bool is_keyframe,
            std::vector<SubsampleEntry>* subsamples) const override;

    private:
        ~AVCBitstreamConverter() override;
        std::unique_ptr<AVCDecoderConfigurationRecord> avc_config_;
    };

} // namespace mp4
} // namespace media

#endif // MEDIA_FORMATS_MP4_AVC_H_
